Abstract: The present invention relates an antifouling electrocatalytic composite membrane and a membrane reactor. The electrocatalytic composite membrane (3) consists of a substrate and a catalytic coating, wherein the substrate is selected from a conductive substrate or a nonconductive substrate coated with a conductive coating, and the substrate is a porous support having supporting, conducting and separating functions. The catalytic coating is supported or coated on the surface and in the pores of the conductive substrate or the conductive coating so as to increase the electrocatalytic activity of the substrate.